FR2804616A1 - FILTERING APPARATUS AND OPENING / CLOSING VALVE FOR THE FILTERING APPARATUS - Google Patents

Abstract

Filter apparatus comprising a tank (8), a coated filter layer (82) formed by a filter aid (F) on a filter bed (81) between an unfiltered liquid chamber (83) and a liquid chamber filtered (84); an inlet pipe (1), comprising a pump (P), a first valve (V1); an outlet pipe (2), comprising a second valve (V2); an adjuvant piping (5), a coating liquid outlet (85), a filter adjuvant adding element (t); a bypass pipe (3) for the coating, a third valve (V3); and a bypass pipe (4) for valve cleaning, going from an outlet (91a) at the bottom of an inlet part (91) of the second valve (V2), to the inlet of the pump ( P) by a fourth valve (V4).

Description

FILTERING APPARATUS AND OPENING / CLOSING VALVE

FOR THE FILTERING APPARATUS

  The present invention relates to a filtering apparatus, specifically a filtering apparatus comprising a filtering tank, in which a coated filtering layer is formed with the aid of a filtering aid on a filtering bed between a unfiltered liquid chamber, into which an unfiltered liquid to be filtered is introduced, and a filtered liquid chamber, so that the unfiltered liquid introduced into the unfiltered liquid chamber is filtered while moving through the layer of coated filtering towards the filtered liquid chamber to

  be extracted from the filtered liquid chamber.

  The present invention also relates to an opening / closing valve for the filtering apparatus. Various processing liquids, such as plating liquid, dyeing liquid, liquid photographic developer and ordinary cleaning liquid, are commonly filtered for reuse by a filtering apparatus which includes a

pump and a filter tank.

  This is due to increases in impurities, since liquids are used repeatedly, such as impurities transported with the object to be treated, impurities produced due to a change in quality, deterioration of treatment

  and / or external impurities falling into liquids.

  Purification and filtering of liquids are also commonly adopted for liquids such as liquid industrial chemicals,

  liquid pharmaceuticals and beverages.

  A classic example of the foregoing filter apparatus is a filter apparatus comprising a filter tank, in which a coated filter layer is formed using a filter aid (filter material) on a filter bed between an unfiltered liquid chamber, into which an unfiltered liquid to be filtered is introduced, and a filtered liquid chamber, so that the unfiltered liquid introduced into the unfiltered liquid chamber can be filtered while moving through the coated filter layer to the filtered liquid chamber to

  be extracted from the filtered liquid chamber.

  Figure 3 is an example of the conventional apparatus. The filtering device of FIG. 3 is provided with a filter tank 8. The filter tank 8 comprises an unfiltered liquid chamber 83 into which an unfiltered liquid L is introduced to be filtered, a filtered liquid chamber 84 and a filter bed 81 therebetween in which a coated filter layer 82 is formed by a filter aid (filter material), so that the unfiltered liquid L, introduced, while being under pressure, by the through an unfiltered liquid inlet port 831 at the bottom of the unfiltered liquid chamber 83, is filtered, while moving through the coated filter layer 82 towards the filtered liquid chamber 84, and a filtered liquid L ′ is extracted via a filtered liquid outlet orifice 841 at the bottom of the chamber

filtered liquid 84.

  In addition to the filter tank 8, the filter device 8 of FIG. 3 comprises the following: 1) a pipe for introducing unfiltered liquid 1 for introducing the unfiltered liquid L to be filtered into the liquid chamber unfiltered 83 through the unfiltered liquid inlet 831 of the unfiltered liquid chamber, which includes a pump P, a first open / close valve (valve can be opened and can be closed ) Vl connected to a suction port of pump P and a non-return valve V7, located between a discharge port of pump P and the unfiltered liquid inlet port 831 of the non-liquid chamber filtered, 2) a filtered liquid outlet pipe 2, comprising a second opening / closing valve V2, for extracting the filtered liquid L 'via the filtered liquid outlet orifice 841 from the liquid chamber filtered 84, 3) bypass piping 3 for the mix age, going from the filtered liquid outlet orifice 841 of the filtered liquid chamber 84 to the suction port of the pump P via a third opening / closing valve V3, for a representation more detailed according to the example in the figure, a bypass pipe 3 for the coating, going from a liquid flow diversion point M2, located between the filtered liquid outlet orifice 841 of the filter tank 8, and the second opening / closing valve V2 of the filtered liquid outlet pipe 2, at a confluence point M3, located between the pump suction port and the first opening / closing valve V1 of the unfiltered liquid introduction pipe 1, via the third opening / closing valve V3, and 4) a filter aid introduction pipe 5, going from a liquid outlet orifice of coating arranged in advance 85 (for example, a liquid outlet orifice coating e arranged at the unfiltered liquid chamber 83, or according to the example of the figure, a coating liquid outlet orifice arranged in advance on an upper part of the unfiltered liquid chamber 83) of the filter tank 8, at a confluence point of liquid flow Ml, located between the pump suction orifice and the first opening / closing valve V1 of the piping

  for introducing unfiltered liquid 1.

  The introduction pipe 5 is, although not limited to this, according to the example in the figure, a pipe going from the coating liquid outlet orifice 85 to the suction orifice of the pump P, via a fifth opening / closing valve V5, a filter additive addition element t and a sixth opening / closing valve V6. The filter aid additive element (filter material) t, according to the example in the figure, is formed in the form of a reservoir provided with an opening, for the addition of the filter aid or analogous, made on the upper part. A lower end 511 of a pipe 51, going from the coating liquid outlet orifice 85 of the filter tank 8 to the filter adjuvant adding element t via the fifth valve opening / closing V5, is inserted and opened in the tank t. A liquid outlet orifice at the bottom of the tank t is connected to the confluence point of liquid flow Ml, located just before the suction port of the pump, a pipe 52 having the sixth

  V6 opening / closing valve between them.

  The reference PG in the drawing is a pressure gauge for measuring the pressure in the filter tank 8. When the filter device is in a normal liquid filtering operation, only the valves V1 and V2 are open, all the others open / close valves of the plurality of open / close valves being closed. Under this condition, pump P is started. The unfiltered liquid L to be filtered is sucked into the pump P via the valve V1 and is discharged from the pump P to flow into the unfiltered liquid chamber 83 via the non-return valve. V7. The unfiltered liquid L in the unfiltered liquid chamber 83 flows into the filtered liquid chamber 84 under the discharge pressure of the pump through the coated filter layer 82 formed in advance by the filter aid. At this time, the unfiltered liquid is filtered. The filtered liquid L ′ flows to a predetermined location (not shown) through the filtered liquid outlet 841 of the filtered liquid chamber 84 and through the valve.

opening / closing V2.

  The liquid in the filter tank 8 begins to flow back to the pump P when the filtering operation ends with the stop of the pump P or when the pump is stopped due to an electrical power cut . However, the flow is stopped by the non-return valve V7, so that the liquid

  in the filter tank 8 remains in the tank.

  The coated filter layer 82 is formed, for example, as follows: The opening / closing valve V2 of the filtered liquid outlet pipe 2, the opening / closing valve V3 of the bypass pipe 3 for the coating and the sixth opening / closing valve V6 of the pipe 5 are closed, when the filter tank 8 is free of any liquid inside, as immediately after the installation of the filter device, or is cleaned and free of all liquids. On the other hand, the opening / closing valve V1 of the non-filtered liquid introduction pipe 1 and the fifth opening / closing valve V5 of the pipe 5 are open. Under this condition, the pump P is started, when water W to prime the pump is introduced into the tank for adding filtering aid t and

valve V6 is open.

  The pump P. while sucking the water W to prime it, begins to suck the unfiltered liquid L. The unfiltered liquid is thus introduced into the filter tank 8 in this way, bringing the air out into the tank filter 8 through the coating liquid outlet orifice 85 and also the piping 51. The filter tank is filled with

liquid in this way.

  The liquid in the filter tank thus begins to flow through the coating liquid outlet orifice 85 on the upper part of the filter tank and descends towards the tank t, which is ensured by cleaning personnel. knowing that the filter tank 8 is filled with a quantity

predetermined liquid.

  We continue to introduce priming water to prevent air from being sucked in by the pump, until the reservoir t is supplied with the liquid through the liquid outlet orifice.

coating 85.

  When the filter tank 8 is filled with the predetermined quantity of liquid, the pump P being always in operation, the opening / closing valve V3 of the bypass piping 3 for the coating is open, the opening valve / closure Vi of the liquid introduction pipe 1 is closed and then the filter aid (filter material) F is added to the filter aid add tank t. Air, sucked into the filter tank 8 when the filter aid F is added, is purged from the valve V5 and also from the piping 51. Upon completion of the addition of the filter aid F and air purge in the tank

  filtering 8, the valves V5 and V6 are closed.

  The liquid is circulated from the pump P to the unfiltered liquid chamber 83 of the filter tank, the filtered liquid chamber 84, the bypass piping 3 for coating and back to the pump P. During circulation, the filter aid F is deposited on the filter bed 81 to form the coated filter layer

predetermined 82.

  After the formation of the coated filter layer 82, a normal filtering operation is possible, by opening the valve V1 of the liquid introduction pipe 1 and then by opening the valve V2 of the liquid outlet pipe 2, the bypass valve V3 3 being

closed.

  When using the filtering device, problems can occur, as shown in the following document, when a normal operation is started daily after stopping the pump the previous day to end a period scheduled operation, an operation

  scheduled daily for example.

  The coated filter layer 82 may be damaged due to partial detachment of the filter aid from the coated filter layer, caused by a pressure drop in the unfiltered liquid chamber at the time of stopping the pump. Alternatively, the coated filter layer 82 may be damaged due to partial detachment of the filter aid from the coated filter layer 82 caused by mixing or agitation when the pump is restarted, the air drawn from a part forming an axial seal of the pump or the like during a previous filtering operation in order to remain in the upper part of the tank

filtering 8.

  In order to restore the coated filter layer thus damaged, the filter aid which can, for example, float or be deposited in the unfiltered liquid chamber 83 is again made fixed or deposited on the filter bed 81 in advance, using the piping 5 and the bypass piping 3 for the coating, as previously described without additional addition of filter aid or without additional addition of

the latter on a required basis.

  However, the filtering device such as the

previous has the following problem.

  To form the coated filter layer 82, the opening / closing valve V3 of the bypass piping 3 for the coating is open to circulate the liquid through the filter tank 8, thus, at an initial stage of the formation of the coated filter layer, the filter aid and part of the mud in the unfiltered liquid chamber leak from the unfiltered liquid chamber 83 to the filtered liquid chamber 84, and come from the liquid chamber filtered 84 to a liquid inlet part of the opening / closing valve V2, via the liquid flow bypass point M2 of the liquid outlet pipe 2, and remain in the part of valve liquid inlet

  V2 and also in the piping to the latter.

  Because of this, the filter aid, particularly a fine filter aid, the slurry in the liquid and the like, which have passed through the filter bed while the filter bed 81 is not completely coated, remain and / or settle in an area such as the liquid inlet part of the valve and in the piping to the latter. Sludge and / or filter aid among other things which have thus settled and / or settled become floating in the filtered liquid which should be cleaned, during the normal operation to filter the unfiltered liquid after completion of the

  formation of the coated filter layer.

  Therefore, a defective product tends to be made when treating the product with the filtered liquid, such as a mud plating and / or the like, fixed above the treated product. Also, it is difficult to obtain a purified liquid at a desired level for liquid industrial chemicals, liquid pharmaceuticals,

drinks or the like.

  In addition to the above, we also observe

the problems below.

  The filter tank 8 is usually installed on a base located on an elevation from the ground of the filter device to take account of piping and the like. The non-return valve V7, along the piping between the pump outlet port P and the unfiltered liquid inlet port 831, is in a vertical position, the liquid inlet port being down and the outlet up, making the base very high, making it run

  the most risk to staff working there.

  In addition, when the pump P is stopped, a partially detached filter aid and the like of the coated filter layer 82, returning towards the non-return valve, tend to cause a

  V7 non-return valve malfunction.

  An object of the invention is to provide a filtering device, comprising a filtering tank, in which a coated filtering layer is formed by a filtering aid (filtering material) on a filtering bed between a chamber of non-liquid filtered, into which an unfiltered liquid to be filtered is introduced by means of a pump, and a chamber of filtered liquid, so that the unfiltered liquid introduced into the chamber of unfiltered liquid is filtered while moving through the filter layer coated towards the filtered liquid chamber to be extracted from the filtered liquid chamber and also comprising a tubing for coating the filter bed with the filter aid using the unfiltered liquid, in which the sludge parking , part of the filter aid and the like in the unfiltered liquid used for coating is removed in a pipe to extract the filtered liquid from the c filtered liquid chamber and thus a cleaner filtered liquid is obtained during a normal filtering operation after

  the formation of the coated filter layer.

  Another object of the invention is to provide the previous filtering apparatus, in which a base is made lower, if the filter tank is located on the base, to make working on the base safer, and in which part of the filter aid and / or the like detached from the coated filter layer, when the pump stops, does not easily return to a non-return valve installed along a pipe for the introduction of unfiltered liquid into the unfiltered liquid chamber of the filter tank, and therefore the harmful effect on the non-return valve and moreover on an upstream part forming the axial seal of the pump, by the detached filter aid and the like is removed and thus a filtering operation

  correct and effective is maintained for a long time.

  Yet another objective of the invention is to provide an opening / closing valve (which can be opened and closed), for the filtering apparatus comprising the filtering tank and the piping for coating the previously mentioned filtering bed , which is to be installed along the piping to extract the filtered liquid from the filtered liquid chamber and capable of eliminating the sludge parking, of part of the filter aid and the like in the unfiltered liquid used for the coating, in the piping to extract the filtered liquid from the filtered liquid chamber so that a cleaner filtered liquid is obtained during a normal filtering operation after the formation of the

coated filter layer.

  The invention provides a filtering device and / or an opening / closing valve (which can be opened

and closed) for the device.

  The invention relates first of all to a filtering apparatus comprising: a filtering tank, in which a coated filtering layer is formed by a filtering aid (filtering material) on a filtering bed between an unfiltered liquid chamber having an unfiltered liquid inlet port, through which an unfiltered liquid to be filtered is introduced, and a filtered liquid chamber having a filtered liquid outlet port, so that the unfiltered liquid introduced through the via said inlet port for unfiltered liquid into the unfiltered liquid chamber is filtered while moving through said coated filter layer to said filtered liquid chamber to be extracted from said filtered liquid chamber through the filtered liquid outlet; an unfiltered liquid introduction pipe, comprising a pump and a first opening / closing valve connected to a suction orifice of said pump, for introducing the unfiltered liquid to be filtered into said chamber of liquid not filtered by the 'through said unfiltered liquid inlet port; a filtered liquid outlet pipe, comprising a second opening / closing valve, for extracting the filtered liquid through the filtered liquid outlet orifice from said filtered liquid chamber; a filter aid introduction pipe which can be opened and closed, comprising a filter aid addition element, going from a coating liquid outlet orifice arranged in advance of said tank. one-part filtering between the suction port of the pump and the first valve for opening / closing said piping for introducing unfiltered liquid; a bypass piping for the coating, going from a part between said filtered liquid outlet orifice and the second opening / closing valve of said filtered liquid outlet piping, to a part between the suction port the pump and the first opening / closing valve of said non-filtered liquid introduction pipe, by means of a third opening / closing valve; and a bypass piping for valve cleaning, going from a liquid inlet part of the second opening / closing valve of said filtered liquid outlet piping, to a part between the suction port of the pump and the first opening / closing valve of said non-filtered liquid introduction pipe, via a fourth opening / closing valve. The filtering apparatus can be characterized in that said non-filtered liquid introduction pipe has a non-return valve between a liquid outlet orifice of said pump and the unfiltered liquid inlet orifice of said room of

unfiltered liquid.

  The filtering apparatus can be characterized in that said non-return valve is installed along a part of horizontal or almost horizontal pipe in a horizontal or almost position

  horizontal to have a low height.

  The filtering apparatus can be characterized in that said second opening / closing valve is an opening / closing valve having a liquid outlet part above and said liquid inlet part below, a valve seat being therebetween, in which a valve body can be brought into or out of contact, a liquid outlet port is formed at the bottom of the downwardly most curved portion of said liquid inlet portion and said bypass piping for valve cleaning is connected to said liquid outlet port of the

liquid inlet part.

  The invention also relates to an opening / closing valve for a filter apparatus comprising a filter tank, in which a coated filter layer is formed by a filter aid (filter material) on a filter bed between a chamber of unfiltered liquid having an unfiltered liquid inlet port, through which an unfiltered liquid to be filtered is introduced, and a filtered liquid chamber having a filtered liquid outlet port, so that the liquid does not filtered material introduced through said inlet port of unfiltered liquid into the filtered liquid chamber is filtered while moving through said coated filter layer to said filtered liquid chamber to be extracted from said filtered liquid chamber through the filtered liquid outlet; an unfiltered liquid introduction pipe, comprising a pump and a first opening / closing valve connected to a suction orifice of said pump, for introducing the unfiltered liquid to be filtered into said chamber of liquid not filtered by the 'through said unfiltered liquid inlet port; a filtered liquid outlet pipe, comprising a second opening / closing valve, for extracting the filtered liquid through the filtered liquid outlet orifice from said filtered liquid chamber; a filter aid introduction pipe which can be opened and closed, comprising a filter aid addition element, going from a coating liquid outlet orifice pre-arranged from said filter tank, to a part between the suction port of the pump and the first valve for opening / closing said piping for introducing unfiltered liquid; and a bypass piping for the coating, going from a part between the filtered liquid outlet port and the second valve opening / closing said filtered liquid outlet pipe, to a part between the port d suction of the pump and the first opening / closing valve of said non-filtered liquid introduction pipe, by means of a third opening / closing valve; wherein: said opening / closing valve for the filtering apparatus is a valve used as said second opening / closing valve in said filtered liquid outlet pipe, and has a liquid outlet port at the bottom a liquid inlet part of the valve to extract, with the liquid,

  impurities in the liquid inlet part.

  The opening / closing valve according to the invention and the opening / closing valve in the filtering device according to the invention, for example, the second opening / closing valve of the filtered liquid outlet pipe can be of different types, as long as they can be opened or closed. Different types of manual valves and / or

  automatic valves can be used.

  The opening / closing valve can be characterized in that the opening / closing valve has a liquid outlet part above and said liquid inlet part below, a valve seat being between them, wherein a valve body can be brought into or out of contact, and said liquid outlet port is formed at the bottom of the most curved downward portion of said liquid inlet portion. The foregoing objectives and other objectives, features, aspects and advantages of the present invention will become more evident on reading the

  detailed description which follows of this

  invention when taken in conjunction with the accompanying drawings. Figure 1 is a schematic perspective view of an example of the filter apparatus according to the invention; Figure 2 is an enlarged cross-sectional view of a portion of the filtered liquid outlet piping; Figure 3 is a schematic perspective view

  of a conventional filtering device.

  A preferred embodiment of the filter apparatus according to the invention comprises a filter tank, a pipe for introducing an unfiltered liquid to be filtered into the filter tank, a pipe for extracting a filtered liquid from the filter tank, a filter additive introduction pipe, a bypass pipe for the coating and a bypass pipe for the

valve cleaning.

  The filter tank is a filter tank in which a coated filter layer is formed by a filter aid (filter material) on a filter bed between an unfiltered liquid chamber having an unfiltered liquid inlet port through which the unfiltered liquid to be filtered is introduced, and a filtered liquid chamber having a filtered liquid outlet port, so that the unfiltered liquid introduced into the unfiltered liquid chamber through the unfiltered liquid inlet port can be filtered while moving through the coated filter layer to the filtered liquid chamber and the filtered liquid can be extracted through the outlet port

  of filtered liquid from the filtered liquid chamber.

  The unfiltered liquid introduction pipe is used to introduce the unfiltered liquid to be filtered into the unfiltered liquid chamber via the unfiltered liquid inlet orifice and comprises a pump and a first valve. open / close (can be opened and closed) connected to an orifice

of the pump.

  The filtered liquid outlet pipe is used to extract the filtered liquid through the filtered liquid outlet port of the filtered liquid chamber and includes a second valve

opening / closing.

  The filter additive introduction pipe (filter material) is a pipe that can be opened and closed, going from a coating liquid outlet port pre-arranged from the filter tank, to a part between the pump suction port and the first valve for opening / closing the piping for introducing unfiltered liquid,

  comprising a filter additive adding element.

  The bypass piping for the coating is a piping going from a part between the filtered liquid outlet orifice of the filtered liquid chamber and the second valve opening / closing of the filtered liquid outlet piping, to a part between the suction port of the pump and the first opening / closing valve of the piping for introducing unfiltered liquid, via a third opening / closing valve. The valve cleaning bypass piping is a piping going from a liquid inlet part of the second valve opening / closing the filtered liquid outlet piping, to a part between the suction port pump and the first valve for opening / closing the piping for introducing unfiltered liquid, via a

  fourth opening / closing valve.

  When the filtering device is in a normal liquid filtering operation, only the first opening / closing valve, of the piping for introducing unfiltered liquid, and the second opening / closing valve, of the piping of filtered liquid outlet, are open, all the other opening / closing valves of a plurality of opening / closing valves being closed. On this condition,

the pump is started.

  The unfiltered liquid to be filtered is drawn into the pump via the first open / close valve and is discharged from the pump to flow into the unfiltered liquid chamber of the tank. The unfiltered liquid in the unfiltered liquid chamber flows into the filtered liquid chamber under the discharge pressure of the pump through the coated filter layer formed in advance by the filter aid. At this time, the unfiltered liquid is filtered. The filtered liquid flows to a predetermined location (not shown) through the filtered liquid outlet orifice of the filtered liquid chamber and via the second valve for opening / closing the

  filtered liquid outlet piping.

  The coated filter layer is formed, for example, as follows: The second valve for opening / closing the filtered liquid outlet piping and the third valve for opening / closing the bypass piping for the coating are closed, when the filter tank is free of any liquid inside, as immediately after the installation of the filter device, or is cleaned and free of any liquid. On the other hand, the first valve for opening / closing the pipe for introducing unfiltered liquid and the outlet hole for coating liquid from the filter tank are open. Water to prime the pump is introduced from the filter aid additive element of the

  filter additive introduction piping.

  The filter aid introduction piping can, for example, be the piping going from the pre-arranged coating liquid outlet orifice (for example, the coating liquid outlet orifice arranged on the upper part of the unfiltered liquid chamber of the filter tank), at the part between the suction port of the pump and the first valve for opening / closing the non-liquid introduction piping filtered, by element

addition of filter aid.

  The filter aid additive element may, for example, be formed into a tank shape having an opening, for the addition of the filter aid or the like, made in the upper part. A piping can be arranged, going from the coating liquid outlet orifice of the filter tank to the filter adjuvant adding element via an opening / closing valve, l the lower end of the piping being inserted and open in the tank. The liquid outlet orifice at the bottom of the tank can be connected to the part between the suction port of the pump and the first valve for opening / closing the piping for introducing unfiltered liquid, a tubing having an opening / closing valve being midway

  along the piping itself.

  Water to prime the pump that has already been

  introduced, the pump is started.

  The pump, while sucking up the priming water, begins to suck the unfiltered liquid. The liquid is thus introduced into the filter tank and the tank is filled with the liquid. The liquid in the filter tank begins to flow through the coating liquid outlet port of the filter tank and descends into the filter additive adding element, which is ensured by personnel of implementation knowing that the filter tank is filled with a quantity

predetermined liquid.

  Priming water is continued to prevent air from being drawn in by the pump, until the filter aid additive element is supplied with liquid through of

  the coating liquid outlet port of the tank.

  When the filter tank is filled with the predetermined quantity of liquid, the pump still in operation, the third opening / closing valve of the bypass piping for coating is open, the first opening / closing valve of the liquid introduction pipe is closed and then the filter aid (filter material) is added to the addition element

  filter aid for the inlet piping.

  Upon completion of the addition of the adjuvant

  filtering, the inlet pipe is closed.

  The liquid is circulated from the pump to the unfiltered liquid chamber of the filter tank, the filtered liquid chamber, the bypass piping for coating and back to the pump. During circulation, the filter aid builds up on the filter bed to form the coated filter layer

predetermined.

  To form the coated filter layer, the

  unfiltered liquid including mud is introduced-

  in the filter tank and, upon completion of the addition of the filter aid, the liquid is circulated while the third valve for opening / closing the bypass piping for the coating is open , and then a part of the unfiltered liquid comes to the second valve for opening / closing the filtered liquid outlet pipe to extract the filtered liquid, and tends to park in the liquid inlet part of the

  valve and so in the piping to the latter.

  However, in the filtering device described in this document, there is provided the bypass piping for valve cleaning. By opening the fourth valve for opening / closing the piping at an initial stage of the formation of the coated filter layer, or, at the latest, before the completion of the formation of the coated filter layer, impurities ( sludge and / or a filter aid, particularly a fine particle filter aid, which have passed through the filter bed while the filter bed is not completely coated) in the liquid coming into the inlet part liquid from the second open / close valve can be drawn into the pump. By doing so, it is possible to eliminate the parking of unfiltered liquid, therefore, the parking and / or deposition of filter aid, mud and / or the like, along the piping from the outlet for filtered liquid from the filtered liquid chamber to the liquid inlet part of the second opening / closing valve and also in the liquid inlet part of the second opening / closing valve. Therefore, the cleaner filtered liquid is obtained during a normal filtering operation after the formation of the

coated filtering.

  When using the filtering device, problems can occur, as shown in the rest of the document. After stopping the pump to complete a programmed period of operation, a daily scheduled operation for example, the coated filter layer may be damaged due to partial detachment of the filter aid from the coated filter layer caused by a pressure drop in the chamber

unfiltered liquid.

  When normal operation is restarted the next time (the next day, for example), the coated filter layer may be damaged due to partial detachment of the filter aid from the coated filter layer caused by mixing or agitation, when the pump is restarted, of the air sucked in from the axial seal part of the pump or the like during a previous filtering operation in order to remain in the part

top of the filter tank.

  In order to restore the coated filter layer thus damaged, the filter aid which can, for example, float or be deposited in the chamber of unfiltered liquid can again be made fixed or deposited on the filter bed in advance, using the piping for coating and / or the like, as previously described without additional addition of filter aid or without addition

  additional of the latter on a required basis.

  The liquid in the filter tank begins to flow back to the pump when the filtering operation is completed with the pump stopped or when the pump is stopped due to an electrical power cut. However, this can be prevented, for example by providing the check valve between the discharge port of the pump and the unfiltered liquid inlet port of the unfiltered liquid chamber. It is preferable to install the non-return valve, if installed, in a horizontal or almost horizontal position, along a horizontal or almost horizontal part

  piping to make it lower.

  Installing the check valve in this way means that the check valve portion has a lower height compared to the same check valve installed in a vertical position. If the filter tank is installed on a pedestal, the pedestal can therefore be made lower and safety can be better ensured for personnel working on the pedestal. The check valve prevents the liquid in the unfiltered liquid chamber of the filter tank from flowing back to the pump, when a filtering operation is finished by stopping the pump or when the pump is stopped due to a power cut. Also, the non-return valve is installed in a horizontal or almost horizontal position along the horizontal or almost horizontal part of the piping, thus, the detrimental effect in that the filter aid of the coated filter layer which can be detached when the pump stops, in that part of what is deposited in the filter tank and / or the like, to return to the non-return valve causing a malfunction of the valve or towards the part forming an axial seal of the pump causing wear of this part, is eliminated. Therefore, an operation of

  effective filtering is possible for a long time.

  A preferred embodiment of an opening / closing valve (which can be opened and closed) for a filtering device according to the invention is an opening / closing valve for the filtering device, used as a second opening / closing valve in the outlet pipe of

  filtered liquid from the filtering device.

  The opening / closing valve for the filtering apparatus has a liquid outlet orifice at the bottom of a liquid inlet part for extracting, with the liquid, impurities stationed in the

liquid inlet part.

  The opening / closing valve for the filtering device, by opening the liquid outlet port of the liquid inlet part, can let the

  unfiltered liquid for coating which can park-

  in the liquid inlet part of the valve and / or in the piping towards the latter, with mud, the filter aid and the like contained in the unfiltered liquid. The open / close valve can be used as a second open / close valve in the outlet pipe of

  filtered liquid from the filtering device.

  In the following document, we will describe the filtering device and the second opening / closing valve for the filtering device in

referring to the drawings.

  Figure 1 is an example of the filter apparatus. The filtering device is an improvement on a conventional filtering device represented in FIG. 3. The filtering device represented in FIG. 1 includes an example of the opening / closing valve according to the invention (valve of open / close V2 shown in Figure 2, at

describe later).

  In the filtering device shown in FIG. 1, the bypass pipe 4 for valve cleaning is added, starting at the liquid inlet part 91 (see FIG. 2) of the second opening valve / closing V2 of the filtered liquid outlet pipe 2 and is connected to the suction port of the pump P, via the fourth opening / closing valve V4 and via the

  liquid confluence point M4 at mid

  path along the pipe 52 of the pipe 5. A part going from the valve V2 to the pipe 52 of the pipe 4 has the same diameter or a smaller diameter than the pipe 52. The part going from the valve V2 to the pipe 52 of the piping 4 has a smaller diameter than any of the pipes for piping 1, 2 or 3. The non-return valve V7 is connected laterally in a horizontal or almost horizontal position halfway along the piping 11 which descends vertically from the unfiltered liquid inlet 831 of the unfiltered liquid chamber 83 of the filter tank and then extends horizontally or

almost horizontal.

  The filtering device is identical to that

  shown in Figure 3, with the exception of the previous ones.

  The elements which have the same structures and which function like the elements of the filtering apparatus of FIG. 3 are provided with the same symbols

  than those in Figure 3.

  A normal liquid filtering operation is performed and the coated filter layer is formed in the filter apparatus of Figure 1, as in the conventional filter apparatus shown in Figure 3. Therefore, this aspect is not not to describe. Valve V4 of bypass piping 4 for valve cleaning is closed for a

  normal liquid filtering operation.

  We will write the improved points. The bypass piping 4 for valve cleaning is provided in the filtering device shown in FIG. 1. To form the coated filter layer 82, by opening the fourth opening / closing valve V4 of the piping 4 to 1. initial stage of the formation of the coated filter layer, or, at the latest, before the completion of the formation of the coated filter layer, the liquid which has come into the liquid inlet portion 91 of the second opening / closing valve V2 can be sucked into the pump P. By doing this, it is possible to eliminate the parking of the unfiltered liquid, consequently, the parking and / or the deposit of mud, of a part of the filter aid and / or the like, along the piping from the filtered liquid outlet orifice of the filtered liquid chamber 841 of the filtered liquid chamber 84 to the liquid inlet part 91 of the second opening / closing valve V2 and also nt in the liquid inlet part 91

  of the second opening / closing valve V2.

  Therefore, the cleaner filtered liquid L 'is obtained during a normal filtering operation

  after the formation of the coated filter layer.

  Figure 2 shows the opening / closing valve V2 and adjacent parts in an enlarged manner. The valve V2 is an opening / closing valve having an outlet part of

  liquid above and the liquid inlet part above

  below, a valve seat being between them, in which a valve body can be brought into or out of contact. As shown in FIG. 2, the valve V2 has the liquid inlet part 91, the liquid outlet part 92, the valve seat 93 located between them, the vertically movable valve body 94 which can be in contact with the valve seat in a liquid tight manner, a valve stem 95 to support the valve body, fitted to a valve housing 96 in a vertically movable manner by a threaded mechanism (screw) and a valve flywheel 97 to

  level of the upper end of the rod 95.

  A pipe 41 for forming the bypass pipe 4 for cleaning the valve is connected to a liquid outlet orifice 91a situated at the bottom of the liquid inlet part 91. According to the example shown in FIG. 2, the pipe 41 is connected to a comparatively close location of the liquid inlet orifice of the liquid inlet part 91. If no disadvantage is observed, the liquid outlet orifice 91a can be formed at the bottom of the most curved part towards the bottom of the entry part

  liquid, so the hose can be connected there.

  To show an example with reference to FIG. 2, the liquid outlet orifice 91a can be formed at the bottom of the most domed part downwards 911

  directly under valve body 94.

  As previously described, the non-return valve V7 is connected to a horizontal or almost horizontal part of the pipe 11 in a horizontal or almost horizontal position. Therefore, the non-return valve portion has a lower height compared to the same valve installed in a vertical position. If the filter tank 8 is installed on a base, which is not shown, the base can therefore have a lower height and it is better to guarantee the

  safety of personnel working on the base.

  The non-return valve V7 prevents the liquid L in the unfiltered liquid chamber of the filter tank from flowing back to the pump P, when a filtering operation ends with the stop of the pump P or when pump P is stopped due to a

  power cut. Also, the non-return valve

  back V7 is installed in a horizontal or almost horizontal position along the piping 11, thus, the detrimental effect in that the filter aid which can be detached from the coated filter layer 82 at the time of stopping the pump, in that part of what is deposited in the filter tank 8 and / or the like to return to the non-return valve V7 causing a malfunction of the valve or to the part forming the axial seal of the pump causing wear of this part, is removed. Therefore, an efficient filtering operation is possible for a long time. Although the present invention has been described and shown in detail, it will be clearly understood that the latter is given by way of representation and by way of example only and is not taken by way of limitation, spirit and scope of the present invention being only

  limited by the terms of the appended claims.

Claims (6)

  1. Filtering apparatus, characterized in that it comprises: a filtering tank (8), in which a coated filtering layer (82) is formed by a filtering aid (F) on a filtering bed (81) between an unfiltered liquid chamber (83) having an unfiltered liquid inlet port (831), through which an unfiltered liquid (L) to be filtered is introduced, and a filtered liquid chamber (84) having a filtered liquid outlet (841), so that the unfiltered liquid (L) introduced through said unfiltered liquid inlet (831) into the unfiltered liquid chamber (83) is filtered while moving through said coated filter layer (82) to said filtered liquid chamber (84) to be extracted from said filtered liquid chamber (84) through the filtered liquid outlet ( 841); an unfiltered liquid introduction pipe (1), comprising a pump (P) and a first opening / closing valve (V1) connected to a suction port of said pump (P), for introducing the non-liquid filtered (L) to be filtered in said unfiltered liquid chamber (83) through said unfiltered liquid inlet port (831); a filtered liquid outlet pipe (2), comprising a second opening / closing valve (V2), for extracting the filtered liquid (L ') via the filtered liquid outlet port (841) from said filtered liquid chamber (84); a filter aid introduction pipe (5) which can be opened and closed, comprising a filter aid addition element (t), going from a coating liquid outlet orifice arranged at the advancement (85) of said filter tank (8) to a part between the suction port of the pump (P) and the first opening / closing valve (Vi) of said non liquid introduction pipe filtered (1); a bypass pipe (3) for the coating, going in part between said filtered liquid outlet orifice (841) and the second opening / closing valve (V2) of said filtered liquid outlet pipe (2 ), to a part between the suction opening of the pump (P) and the first opening / closing valve (Vl) of said non-filtered liquid introduction pipe (1), by means of a third opening / closing valve (V3); and a bypass pipe (4) for valve cleaning, going from a liquid inlet part (91) of the second opening / closing valve (V2) of said filtered liquid outlet pipe (2) , to a part between the suction port of the pump (P) and the first opening / closing valve (V1) of said piping for introducing unfiltered liquid (1), via a fourth valve opening / closing (V4).   2. Filtering device according to claim 1, characterized in that said non-filtered liquid introduction pipe (1) has a non-return valve (V7) between a liquid outlet orifice of said pump (P) and the unfiltered liquid inlet port (831) of said liquid chamber unfiltered (83).   3. Filtering apparatus according to claim 2, characterized in that said non-return valve (V7) is installed along a part of horizontal or almost horizontal pipe in a horizontal or almost horizontal position to have a low height.   4. Filtering apparatus according to claim 1, 2 or 3, characterized in that said second opening / closing valve (V2) is an opening / closing valve having a liquid outlet part (92) above and said liquid inlet part (91) below, a valve seat (93) being between them, in which a valve body (94) can be brought into or out of contact, a liquid outlet port (91a) is formed at the bottom of the most curved downward part (911) of said liquid inlet part (91) and said bypass pipe (4) for valve cleaning is connected to said liquid outlet port of the liquid inlet part (91). 5. Opening / closing valve for a filtering device, characterized in that it comprises a filtering tank (8), in which a coated filtering layer (82) is formed by a filtering aid (F) on a filter bed (81) between an unfiltered liquid chamber (83) having an unfiltered liquid inlet port (831), through which an unfiltered liquid (L) to be filtered is introduced, and a filtered liquid chamber (84) having a filtered liquid outlet port (841), so that unfiltered liquid (L) introduced through said unfiltered liquid inlet port (831) into the filtered liquid (84) is filtered while moving through said coated filter layer (82) to said filtered liquid chamber (84) to be extracted from said filtered liquid chamber (84) through the orifice filtered liquid outlet (841); an unfiltered liquid introduction pipe (1), comprising a pump (P) and a first opening / closing valve (Vi) connected to a suction port of said pump (P), for introducing the non-liquid filtered (L) to be filtered in said unfiltered liquid chamber (83) through said unfiltered liquid inlet port (831); a filtered liquid outlet pipe (2), comprising a second opening / closing valve (V2), for extracting the filtered liquid (L ') via the filtered liquid outlet port (841) from said filtered liquid chamber (84); a filter aid introduction pipe (5) which can be opened and closed comprising a filter aid addition element (t), going from a pre-arranged coating liquid outlet port (85) from said filter tank (8), to a part between the suction port of the pump (P) and the first opening / closing valve (Vi) of said non-filtered liquid introduction pipe (1) ; and a bypass piping (3) for the coating, going in part between the filtered liquid outlet orifice (841) and the second opening / closing valve (V2) of said filtered liquid outlet piping (2), at a part between the suction port of the pump (P) and the first opening / closing valve (V1) of said non-filtered liquid introduction pipe (1), via a third opening / closing valve (V3); wherein: said opening / closing valve for the filtering apparatus is a valve used as said second opening / closing valve (V2) in said filtered liquid outlet pipe (2), and has an orifice liquid outlet at the bottom of a liquid inlet part of the valve to extract, with the liquid, impurities in the liquid inlet part. 6. Opening / closing valve according to claim 5, characterized in that the opening / closing valve has a liquid outlet part (92) above and said liquid inlet part (91) au- below, a valve seat (93) being between them, in which a valve body (94) can be brought into or out of contact, and said liquid outlet orifice (91a) is formed at the bottom of the most domed part down (911) of said entry portion of liquid (91).